1991 Yamaha 250TXRP :/

[ArmyVeteranOIF]

I have a 1991 Yamaha 250TXRP that is regularly serviced with 1048 hours. Lately it has had start-up issues after running for a while (example, boating for hours to different fishing stops, then when I attempt to fire it up and move to another location it will not start). It attempts to start but will not crank over, sometimes after a full day of use. The next morning it will fire up on the first try. I then noticed that if I tilt the outboard up a bit it fires up perfectly, almost as if it is being flooded and the tilt up clears the carburetor? Any ideas?

[99yam40]

I would check for good spark when it will not fire up to make sure that is not the problem.
Spark tester or a timing light should show if the individual plugs/cylinders are sparking

[jb123]

do you repump ball at the restarts? check ball firmness, could be losing prime
does yours have the elec external fuel pumps ?

[ArmyVeteranOIF]

Yes I re-pump the bulb and push the control forward a few times, I follow the starting procedures in the owner’s manual. The strange thing is that for a while it would fire up with the outboard tilted up a bit and that will start up after resting overnight? Is a vapor lock possible, if so what is the remedy for that?

[jb123]

may i ask what regularly serviced means to YOU ?

[jb123]

ok over there you DO say you had the carbs redone...8 months ago and that you DO have elec fuel pumps... do you use ethanol ?
use a water separator ?

[Tucker]

Can't help thinking the carb bowls are not filling. Army says he tilts the engine up slightly and she fires right up; maybe bringing the level up enough to start.

[ArmyVeteranOIF]

Good morning, jb123:

I had a mobile marine tech service the engine regularly, I’m not very mechanically inclined, water pump, gear oil, standard service. I have been fueling at the marina lately, good fuel and using Sea Foam. I’m not sure on the water separator, is that something I can replace?

[rodbolt17]

attempts to start but wont crank over.
cant happen.
it either cranks over or it doesnt.
if it cranks over yet fails to start its possible its flooding.
that system uses an electric pump for cold start,accelleration and at knock detect.
holds about 4 PSI on the injector solinoid rail.
as needed based on various input signals, the injectors open to allow more fuel.
a leaking solinoid oring can cause rich idle and hard hot restarts, as can a leaking lift pump.
3.1L motors are rather hard on lift pumps and they are reccomended to be replaced/rebuilt about every three years.

if it fails to crank over orb does it very slow,check cables and connections.

[ArmyVeteranOIF]

Hello, rodbolt17:

Sorry, my terminology is off, it cranks over but fails to start. So if I understand it right, a leaking solenoid o-ring or a worn out lift pump could be my problem?

[rodbolt17]

could be, or the electric fuel enrichment pump is not working,regulator not working or the manual enrichment valve is leaking.
as you tilt the engine up it reduces the fuel level in the bowl causing a leaner A/F mixture.
as the floats are hinged at the rear of the carb as you tilt the rear up and the front down all the fuel sloshes to the front holding the float closed a bit longer.